基础实验题B:线性及非线性LC振荡电路

介绍了第4届全国大学生物理实验竞赛基础性实验试题B的实验内容、参考解答以及竞赛结果的分析.实验包括线性及非线性LC振荡电路的暂态及稳态性质.实验1涉及线性RLC电路,重点考察学生的实验基础知识和能力;实验2在线性LC振荡电路基础上,增加了非线性阻尼器件,要求学生参照线性振荡电路的性质,初步了解非线性振动的性质.该试题旨在考察学生通过实验观察理解概念,探索物理规律的能力.非线性振荡电路部分还可以作为RLC电路实验的拓展补充,初步观察理解非线性振动的现象和性质.     

Probing the QCD phase structure with higher order baryon numbersusceptibilities within the NJL model

Conserved charge fluctuations can be used to probe the phase structure of strongly interacting nuclear matter in relativistic heavy-ion collisions. To obtain the characteristic signatures of the conserved charge fluctuations for the quantum chromodynamics(QCD) phase transition, we study the susceptibilities of dense quark matter up to eighth order in detail, using an effective QCD-based model. We studied two cases, one with the QCD critical end point(CEP) and one without owing to an additional vector interaction term. The higher order susceptibilities display rich structures near the CEP and show sign changes as well as large fluctuations. These can provide us information about the presence and location of the CEP. Furthermore, we find that the case without the CEP also shows a similar sign change pattern, but with a relatively smaller magnitude compared with the case with the CEP. Finally, we conclude that higher order susceptibilities of conserved charge can be used to probe the QCD phase structures in heavyion collisions.     

Second to tenth order susceptibilities of conserved charges within a modified Nambu-Jona-Lasinio model

We discuss the sign and energy dependence of second to tenth order susceptibilities of the baryon number,charge number, and strangeness for the analysis of critical conditions in heavy ion collisions in the LHC and RHIC by applying a modified Nambu-Jona-Lasinio model. This model is fitted to the quark condensate of the lattice QCD result at finite temperature and zero baryon chemical potential. The presence of a critical point made these susceptibilities deviate considerably from a Hadron-Resonance-Gas model that shows no criticality. The sign, magnitude, and energy dependence of these higher order fluctuations hint towards the existence and location of a critical point that could be discovered in future heavy ion collision experiments.